The objective of this proposal is to develop an intravascular imaging detector to identify vulnerable coronary artery plaques. The detector will work by sensing beta or conversion electron radiotracer emissions from plaque-binding radiotracers. Thereby, a signature will be obtained for the 70% of heart attacks that are caused by minimally obstructive vulnerable plaques which are too small to be detected by angiography. This signature will enable targeted and cost effective therapies to prevent acute coronary artery diseases such as: unstable angina, acute myocardial infarction, and sudden cardiac death. Coronary angiography is unable to define the status of the atheroma, and only measures the luminal dimensions of the blood vessel, without providing information about plaque content. Over the past 12 months preliminary work overcome the technical constraints of size, sensitivity and conformance to the intravascular environment and identified technological approaches for the detector. In the first phase of this program we will prepare prototype assemblies for the detector and characterize their performance using potential plaque labeling radiotracers in order to assess the feasibility of the approach for intravascular plaque detection. In Phase II a complete prototype system will be fabricated and evaluated using animal models. PROPOSED COMMERCIAL APPLICATIONS: The commercial and medical value of a device that can enable preemptive treatment of coronary artery disease is self evident. Over 2 million catheterization diagnostic procedures are performed annually worldwide that would immediately qualify for augmentation with catheter based diagnosis of vulnerable plaque.